Circuit interrupter



June 12, 1956 c. H. BAKER 2,7

CIRCUIT INTERRUPTER Original Filed May 22, 1950 4 Sheets-Sheet 1 l I? I.1 I 5: 1

INVENTOR.

June 12, 1956 Original Filed May 22, 1950 C. H. BAKER CIRCUITINTERRUPTER 4 Sheets-Sheet 2 INVENTOR.

June 12, 1956 c. H. BAKER CIRCUIT INTERRUPTER 4 Sheets-Sheet 3 OriginalFiled May 22, 1950 r W w W M m M e ig llll I ELI w ill IN VEN TOR.(ha/"k5 fflia/wr June 12, 1956 c. H. BAKER 2,750,469

CIRCUIT INTERRUPTER Original Filed May 22, 1950 4 Sheets-Sheet 4 5 50-92 Z9 I 4/ I 84 I L96 I l l INVENTOR L99 I C/zarzla flfia/zer,

United. States Patent CIRCUIT INTERRUPTER Charles. H. Baker, Maywood,Ill., assignor to S & C Electric Company, Chicago, Ill., a corporationof Delaware Original application May 22, 1950, Serial No. 163,511, nowPatent No. 2,651,695, dated September 8, 1953. Divided and thisapplication July 13, 1953, Serial No. 367,590.

8 Claims. (Cl. 200-116) This invention relates, generally, to circuitinterrupters andit has particular relation to dropout fuses. Thisapplication is a division of application Serialv No. 163,511, filed May22, 1950, now U. S. Patent No. 2,651,695, granted September 8, 1953.

Among the objects of this invention are: To provide a. simple andeconomical dropout fuse construction of the solid material type; toconstruct the unlatching mechanism. of a dropout fuse in such mannerthat a coil compression spring therein is not distorted when the deviceis automatically unlatched on blowing of the fuse; to secure. adetachable hinge fitting to the lower ferrule of a dropout fuse tube bya U-bolt; to secure a detachable latch. terminal fitting to a radialflange at the upper end of the dropout fuse tube; to utilize both endsof the power spring to perform useful, functions; to maintain contactengagment between contact fingers within the fuse tube arranged toengage a movable rod-like terminal and a conducting tube therein bymeans of the spring that retracts the rod-like terminal when the. fuseblows; to insulate the spring from the rod-like terminal so that nocurrent flows therethrough; to maintain a. fixed air gap between theconducting tube and the movable rod-like terminal while the latter isbeing withdrawn; to provide for assembling the aforesaid internalmechanism in a fuse tube; and to provide for connecting fusible means tothe upper end of a conducting tube which is located at the lower end ofthe fuse tube.

Other objects of this invention will, in part, be obvious and in partappear hereinafter.

The invention is disclosed in the embodiment thereof as shown in theaccompanying drawings and' it comprises features of construction,combination of elements and arrangement of parts which will beexemplified in the construction hereinafter set forth and the scope ofthe application of which will be indicated in the appended claims.

For a more complete understanding of the nature and the scope of thisinvention reference can be had to the following detailed description,taken together with the accompanyingdrawings, in which:

Fig. 1 is a view, in side elevation, of a dropout fuse construction inwhich the present invention is embodied, certain parts being broken awayand other parts being shown in section in order to illustrate moreclearly the details of construction;

Figs. 2A-2B-2C placed one above the other show at an enlarged scale alongitudinal section of the fuse construction shown in Fig. 1, certainparts being shown in elevation;

Fig. 3 is a view, similar to Fig. 2B, and showing a modifiedconstruction;

Fig. 4 is a view, which shows a modified form of anchorage for thefusible means which can be substituted for that illustrated in Fig. 2Cand which may be used in conjunction with, the modification illustratedin Fig, 3;

Fig. 5 is a view, similar to Fig. 2B, and showing a still.

further modification; and

an 2,750,469 Patented June 12, 1956 Fig. 6 is a detailed sectional viewtaken generally along the lines 66 of Fig. 5 and showing at an enlargedscale a modified form of contact construction.

The construction of the fuse tube and operating mechanism is somewhatsimilar to that disclosed in the copending application of Lindell andBaker, Serial No. 663,832, filed April 22, 1946, now abandoned andassigned to the assignee of this application. Certain of the dropoutfeatures. disclosed in. the copending application of Lindell, Serial No.663,834, filed April 22, 1946, now U. S. Patent No. 2,599,186, datedJune 3, 1952, and assigned to the assignee of this application areemployed; The features of the contact construction and mounting thereforshown in the copending application of Lindell, Serial No. 57,346, filedOctober 29, 1948, now U. S. Patent No. 2,578,255, dated December 11,1951, and assigned to the assignee of thisapplication also are used inconjunction with the present invention.

Referring now particularly to Fig. 1 of the drawings it will be observedthat the reference character 10 designates, generally, a dropout fuseconstruction which. is intended for us on circuits energized at avoltage of 69 kv. This voltage is mentioned for illustrative purposessince the present invention can be adapted for use on systems operatingat higher or lower voltages. The. dropout fuse construction 10 ismounted on a channel base 11 which carries upper and lower insulatorstacks 12 and. 13 near its ends. A latch terminal construction, showngenerally at- 14, is carried by the upper insulator stack 12 while ahinge terminal construction, shown generally at 15, is carried by thelower insulator stack 13. The latch and hinge terminal constructions 14and 15: preferably are constructed as disclosed'in the aforesaidcopending U; S. Patent No. 2,578,255, so that the fuse tube describedhereinafter can be employed in conjunction therewith in lieu of the fusetube disclosed in this copending application.

The latch terminal construction 14 includes a pivotally mounted latch 16which carries a roller 17. The roller 17 is. arranged to cooperate witha roller 18 that is carried by a latch arm 19 for the purpose of holdingthe fuse tube in operative position. The latch arm 19-constitutes a partof a detachable latch terminal fitting'that is shown, generally, at 20.Extending upwardly from the fitting 20 is a guide tube 21 on whichistelescoped an unlatching tube 22. This construction is illustrated inmore detail in Fig. 2A. The tube 22 has'an outwardly extending radialflange 23 at its lower end which is arranged to engage the bifurcatedforward end 24 of the latch 16 for raising the roller 17 out of the pathof the roller 18 to permit the fuse tube to swing to the opencircuit-position. As will be described hereinafter, this action. takesplace when the tube 22 is moved upwardly on blowing of the fusibleelement and after the current flow has been interrupted. At the forwardend of the fitting 20 an eye 25 is rockably mounted at 26 and a pair ofarms 27. extend therefrom underneath the flange 23. The purpose of thisconstruction is to provide for receiving the prongof a live line toolfor swinging the fuse tube to they closed position or for manuallyunlatching it. if desired. A contact member. 28, forming a part of thelatch terminal construction 14 is. arranged to have contact engagementwith the fitting 20 for conducting current thereto. Preferably thecontact member 28 is constructed as disclosed in, the copending U. S.Patent No. 2,578,255.

The detachable latch terminal fitting 20 and parts carriedthereby aremounted on the upper end of a fuse tube that is indicated, generally, at29. Except as described. herein, the fuse tube 29 preferably isconstructed as disclosed in the copending application of Lindell andBaker, Serial No. 663,832 now abandoned. However,

other constructions can be employed if desired without departing fromthe scope of the present invention.

At its lower end the fuse tube 29 is rockably mounted on a hinge member31 which forms a part of the hinge terminal construction 15. For thispurpose trunnions 32 project from opposite sides of a detachable hingefitting that is indicated, generally, at 33. The detachable hingefitting 33 has an arcuate seat portion for receiving a cylindrical lowerferrule 34 to which it is clamped by means of a U-bolt 35. Suitable wellknown dowel pin means (not shown) are provided for insuring properalignment of the hinge fitting 33 on the ferrule 34 with the fitting atthe upper end of the fuse tube 29. The hinge fitting 33 includes an eye36 for receiving the prong of a live line tool to permit handling of thefuse tube 29. A contact member 37, preferably constructed as disclosedin the aforesaid copending U. S. Patent No. 2,578,255, provides contactengagement with the hinge fitting 33. Also included with the hingemember 31 is a rubber bumper 38 for partly absorbing the shock incidentto the stopping of the fuse tube 29 when it swings downwardly.

Referring now particularly to Fig. 2A, it will be observed that the fusetube 29 comprises a tube 41 of insulating material, preferably aphenolic condensation product. At its upper end the tube 41 has an uppermetallic ferrule 42 which is secured in position by having itsintermediate portion 43 rolled into a suitable annular groove inperiphery with the upper end of the tube 41. The upper end 44 is spunover a flange 45 which forms a part of an upper terminal ring 46. Thering 46 has a radial flange 47 at its upper end that projects into arecess 48 on the underside of the central portion 49 of the detachablelatch terminal fitting 20.

Bolts 50 and 51, extending parallel to the longitudinal axis of the fusetube 29, project through the central portion 49 into threaded engagementwith the radial flange 47. This construction permits the fitting 20 andparts attached thereto to be reused with another fuse tube 29 once thefuse has blown or it is desired to use another fuse tube for somereason. The bolts 50 and 51 also serve to clamp a flange 52 between thecentral portion 49 and the upper surface of flange 47 and providealignment of the fitting 20 with the hinge fitting 33 and axialalignment with the fuse tube 29. The flange 52 constitutes an integralextension of a conducting tube 53 which extends downwardly into the tube41 for the purpose of providing a current conducting path to themechanism that is illustrated more clearly in Fig. 2B of the drawings.

Still referring to Fig. 2A of the drawings, it will be observed that ashoulder 56 is formed on the guide tube 21 and that the radial flange 23is held in engagement therewith by a coil compression spring 57. Thelower end of the spring 57 bears against an upstanding part of theflange 23, as shown, and its upper end bears against the under side of acollar 58 which is secured to the upper end of the guide tube 21. Asdescribed hereinafter, when the fuse blows, a member moves upwardlythrough the guide tube 21 and engages a cap 59 which is carried at theupper end of the unlatching tube 22. This lifts the flange 23 forraising the latch 16 in a manner previously described. It is desirableto prevent the spring 57 from being distorted which might be the casewhen the unlatching tube 22 is moved upwardly under considerable force.Unless means are provided for preventing such distortion, the spring 57may go solid and may be permanently distorted so that it would not bereusable. For this purpose a stop sleeve 60 is located in the spacebetween the telescoped tubes 21 and 22. The length of the stop sleeve 60is such that the tubes 21 and 22 cannot be moved far enough apart topermit the spring 57 to go solid.

Referring now to the portion of the construction illustrated in Fig.213, it will be observed that the tube 41 is provided with a liner 63for reinforcing the same. Preferably the liner 63 is formed of fiber.Within the liner 63 cakes 64 of arc extinguishing material, such asboric acid, are inserted, preferably as disclosed in the copendingapplication of Lindell and Baker, Serial No. 663,832, now abandoned. Thecakes 64 of are extinguishing material are apertured to provide alongitudinally extending bore 65 through which a rod-like terminal 66 islongitudinally movable. At the upper end of the liner 63 a reinforcingring 67 is located. Preferably it is formed of fiber and is threadedinto the liner 63. At its upper end the rod-like terminal 66 has a nut68 on a threaded extension 69. The purpose of this construction will bedescribed presently. The nut 68 has a cylindrical contact surface 70that is arranged to be engaged by contact fingers 71. The diameter ofthe cylindrical contact surface 70 is greater than that of the rod-liketerminal 66 to permit free movement of the latter past the contactfingers 71. The upper ends 72 of the contact fingers 71 are curved toprovide a convex contact surface for engaging the cylindrical contactsurface 70 on the nut 69 while the other side is concave for receiving agarter spring 73 which urges the upper ends of the contact fingers 71into good contact engagement with the contact surface 70. The contactfingers 71 are formed in a tubular member of good conducting materialwhich has resilient characteristics. The contact fingers 71 extendupwardly from a cylindrical base portion 74 which has an outstandingradial flange '75 that overlies and is in contact engagement with theupper surface of a radially inwardly extending flange 76 formedintegrally with the conducting tube 53 at its lower end.

The flange 75 is loosely mounted on the flange 76 and they are held ingood contact engagement by means of a coil compression spring 77 whichalso acts to move the rod-like terminal 66 upwardly when the fuse blows.At its lower end the spring 77 reacts against the upper side of theflange 75 and at its upper end it bears against the under side of aninsulating washer or head member 78. Preferably the washer 78 is formedof good insulating material such as a phenolic condensation product. Itis provided to prevent any current flowing through the spring 77 which,particularly under short circuit conditions, might be sufficient toanneal the convolutions thereof and prevent it from biasing the rod-liketerminal 66 in the manner described. The insulating washer 78 has ahexagonal opening 79 in its under side for telescoping with the upperend of a hexagonally shaped arcing rod extension 80. The lower end 81 ofthe arcing rod extension is threaded on the extension 69 and lockedagainst the upper side of a hexagonal head or flange 68 which is formedintegrally with the nut 68. At its upper end the arcing rod extension 80has a threaded shank 82 on which a hexagonal nut 83 can be threaded forholding the insulating washer 78 in position. The nut 83 interfits witha hexagonal opening 83 in the upper side of the washer 78 to preventrelative turning. Openings 84 are provided in the upper surface of theinsulating washer 78 for receiving a spanner wrench. The manner in whichthe mechanism within the tube 41 is assembled will be describedhereinafter.

In Fig. 20 of the drawings the details of construction of the lower endof the fuse tube 29 are illustrated more clearly. It will be observedthat the liner 63 extends to the extreme lower end of the tube 41. Belowthe lowermost cake 64 of arc extinguishing material throat members 88and 89 are positioned. The member 88 is formed preferably of boric acidand the member 89 of fiber.

At the lower end of the rod-like terminal 66 fusible means, showngenerally at 90, are connected. The fusible means 90 includes a strainelement 91 and a fusible element 92. Where the fuse is to be employed ina circuit in which the normal current flow is of the order of only a fewamperes, then the strain element 91 only need be employed. Where thefuse is intended to conduct higher currents the fusible element 92,which may be formed of silver, also is employed. The strain element 91is looped over a transverse pin 93 which is carried by a relativelythick walled metallic terminal tube 94. A stud 95 projects radiallyinwardly from the terminal tube 94 for receiving one end of the fusibleelement 92 if the same is used.

The terminal tube 94 is located at and carried by the upper end of aconducting tube 96 the purpose of which is described in the copendingapplication of Lindell and Baker, Serial No. 663,832, now abandoned. Thelower end 97 of the conducting tube 96 is flared outwardly and issecured by rivets 98 to the inwardly flared lower end 99 of the lowerferrule 34. It will be observed that the ferrule 34 has an annulargroove 100 intermediate its ends for securing it to the tube 41 and forlocating and centering the U-bolt 35. By positioning the U-bolt 35 inthe annular groove 100, it is possible for the hinge fitting 33 andlower ferrule 34- to withstand the mechanical shock incident to theupward recoil of the fuse tube 29 without slipping when it is calledupon to interrupt heavy fault current and retain the fuse tube 29 inposition on the hinge terminal construction 15.

The manner in which the fuse tube 29 and parts associated therewith areassembled will now be described. The lower and upper ferrules 34 and 42are secured to the ends of the tube 41 by a rolling operation. Next thecakes 64 of arc extinguishing material are inserted. Thereafter thereinforcing ring 67 and the throat members 88 and 89 are placed inposition.

Prior to assembly with the tube 41 the lower conducting tube 96 isattached to the metallic terminal tube 94.

The transverse pin 93 is inserted in the tube 94 through the loop in thestrain wire 91. The stud 95, with one end of the fusible element 92attached thereto, is riveted in position in the wall of the tube 94. Thelower end of the rod-like terminal 66 is secured to the upper ends ofthe strain wire 91 and the fusible element 92. This complete assemblythen is dropped into the tube 41 in the upsidedown position. The lowerend 97 of the conducting tube 96 is secured by the rivets 98 to thelower end 99 of the lower ferrule 34.

Outside of the tube 41 the upper terminal ring 46 is assembled with theupper end of the conducting tube 53. This assembly is then inserted inthe upper end of the tube 41 and the upper end 44 of the upper ferrule42 is spun over the flange 45. The contact fingers 71 now are placed inthe lower end of the upper conducting tube 53. Then the nut 68 isthreaded onto the extension 69 by means of a tubular socket wrench whichis large enough to accommodate the hexagonal head 68. The threads on thenut 68 and extension 69 are free running so that there is no tendency totwist the rod-like terminal 66 while the nut 68 is being turned down. Itis undesirable to twist the rod-like terminal 66 in order that any unduestress on the strain element 91 and the fusible element 92 is avoided.Now the hexagonally shaped arcing rod extension 80 is inserted throughthe tubular wrench which is holding the head 68' of the nut 68. The areaof the wrench holding the hexagonal head 68' is such that another socketwrench can be telescoped therewith for the purpose of threading the freerunning extension 80 onto the threaded extension 69. Initially the nut68 is screwed down so that its lower end lightly abuts the upper end ofthe large diameter portion of the rod-like terminal 66. After the arcingrod extension 88 has been threaded into position, where its threadedopening bottoms on the upper end of the extension 69, the nut 68 isbacked off until it is locked in engagement with the lower end of thearcing rod extension 80. This is accomplished by holding stationary thewrench which grips the arcing rod extension 80 and rotating the wrenchwhich grips the head 68 of'the nut68.

fit

its lower end engages the upper surface of the flange 75.'

The spring 77 is compressed by inserting the insulating washer 78 untilit is stopped by the upper end of the arcing rod extension 80 with theshank 82 projecting therethrough. A spanner wrench is inserted in theopenings 84 to hold the washer 78 stationary while the nut 83 is appliedto the threaded end of the shank 82 by a tubular socket wrench. Thisavoids turning of the rod-like terminal 66 and parts attached thereto.On release of the washer 78, the spring 77 moves it upwardly slightly sothat the nut 83 interfits with the hexagonal socket 83. This completesthe assembly of the fuse tube 29. When assembled as described equalforces at the ends of the power spring 77 are applied through therod-like terminal 66 to the strain element 91 at one end and to theflange 75 of the contact fingers 71 at the other end, thereby providingcontact pressure with the flange 76. Now it will be understood that itcan be assembled with the latch terminal fitting 20 at the upper end andthe hinge fitting 33 at the lower end for mounting in a dropout fusemountmg.

In operation, when the fusible means blows, the rodlike terminal 66 nolonger is restrained. Since the pin 93' and the stud 95 are secured tothe tube 94-, there are no parts which are expellable downwardly. Thecoil compression spring 77 expands and withdraws the rod-like terminal66 upwardly to a position where its lower end may be located along thebroken line 101 in Fig. 213. Before the lower end of the rod-liketerminal 66 reaches this position the upper end of the shank 82 engagesthe underside of the cap 59 and moves the unlatching tube 22 upwardly.Thismoves the radial flange 23 in the same direction and lifts the latch16. The roller 17 is moved out of the path of the roller 18, whereuponthe fuse tube 29 can swing about the hinge member 31 downwardly toprovide an air gap in the circuit in addition to the gap which isprovided within the fuse tube 29'.

As soon as the nut 68 moves upwardly so that its contact surface '79nolonger engages the upper ends 72 of the contact fingers 71, an arc isdrawn between the contact fingers 71 and the rod-like terminal 66 unlessit so happens that the surface of the rod-like terminal 66 bears againstone of the contact fingers 71. As will appear hereinafter provision ismade for fixing the length of such an are so that it is not left as asomewhat indeterminate matter as is the case when the constructionillustrated in Fig; 2B is employed.

Referring now particularly to Fig. 3 of the drawings there isillustrated a construction which may be employed in lieu of thatillustrated in Figure 213. If it is desired to fasten the flange 75- atthe lower end of the contact fingers 71 to the flange 76 to take care ofhigher current ratings, this may be accomplished by means ofrivets 104,which,

as illustrated, extend through the flanges 75 and 76' and hold themsecurely together. Instead of employing the rod-like terminal 66 withthe arcing rod extension 80, a single continuous rod-like terminal 105'is employed. It has a contact sleeve 106having a press fit with aknurled portion of the rod-like terminal 165 as shown, for engaging theupper end-s 72 of the contact fingers 71. The rod-like terminal projectsthrough an insulating washer 107 which holds the spring 77 in compressedcondition. A snap ring 108 interfits with the upper end of the rod-liketerminal 165 and holds the insulating washer 107 in the position shown.

In Fig. 4 of the drawings there is shown a construction which can beemployed for fastening to the lower end of the fusible means in lieu ofthat illustrated in Fig. 2C. As shown in Fig. 4 a bridge member 111bears against the lower end of the metallic terminal tube 94. It carriesa stud 112 to the upper end of which the lower ends of the strainelement 91 and fusible element 92 are secured.

Nuts 113 are threaded on the lower end of the stud 112 to secure it inposition on the bridge member-111. It will be understood that thealternate construction illustrated in Fig. 4 can be employed inconjunction with the alernate construction shown in Fig. 3 or that itcan be employed in lieu of the construction illustrated in Fig. 2C inconjunction with the construction illustrated in Fig. 2B.

In Fig. 5 of the drawings an alternate construction is illustrated whichmay be employed in lieu of those illustrated in Figs. 2B and 3. As thereshown, a rod-like terminal 116 is arranged to be moved endwise throughthe bore 65 formed in the cakes 64 of arc extinguishing material. Alsoit moves through a reinforcing ring 117. At its upper end the rod-liketerminal 116 has a threaded extension 118 which is screwed into thelower enlarged end 119 of an arcing rod extension 120. At its upper endthe arcing rod extension 1211 has a threaded shank 121 which projectsthrough an insulating washer 122 against which the upper end of the coilcompression spring 77 reacts. A nut 123 is threaded on the shank 121 forsecuring the washer 122 in position. The lower end 119 of the arcing rodextension 120 has a cylindrical contact surface 124 that is arranged tohave contact engagement with annularly curved portions 125 of generallysector shaped contact members 126 shown more clearly in Fig. 6 of thedrawings. The contact members 126, four in number, have flange portions127 which slide radially over the flange 76 at the lower end of theconducting tube 53. As shown by the upper two contact members 126 inFig. 6, their radial inward movement is limited by their engaging radialsides to provide ample clearance for the rod-like terminal 116. A garterspring 128, surrounding the annularly curved portions 125, acts to biasthe inner surfaces thereof into good contact engagement with thecylindrical contact surface 124. As described hereinbefore in connectionwith Fig. 2B, the spring 77 provides contact pressure between the flangeportions 127 and the flange 76.

It is desirable, as pointed out previously, to provide a fixed gap forthe are which is formed when the rod-like terminal, such as the terminal116, moves out of engagement with the contact members, such as theannularly curved portions 125 of the contact members 126. For thispurpose a metallic washer 129 is positioned on the upper end of thereinforcing ring 117 underneath the flange 76 and in contact engagementtherewith. Now, when the contact surface 124 moves out of engagementwith the curved portions 125, a fixed gap 130 will be maintained withthe rod-like terminal 116 as it is withdrawn through the bore 65 by thecoil compression spring 77.

Since certain further changes can be made in the foregoing constructionand different embodiments of the invention can be made without departingfrom the spirit and scope thereof, it is intended that all matter shownin the accompanying drawings and described hereinbefore shall beinterpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. In a dropout fuse construction wherein a member is released forlongitudinal movement under the influence of a spring to unlatch a fusetube, in combination, a terminal fitting adapted to be detachablysecured to one end of said fuse tube, a guide tube carried by saidfitting through which said member is movable, an unlatching tubeslidably mounted on said guide tube for unlatching said fuse tube, acoil compression spring reacting between said tubes and arranged to becompressed further when said member engages said unlatching tube, andstop means between said tubes limiting their relative movement when saidmember engages said unlatching tube and moves the same to prevent saidspring from going solid.

2. In a dropout fuse construction wherein a member is released forlongitudinal movement under the influence of a spring to unlatch a fusetube, in combination, a terminal fitting adapted to be detachablysecured to one end of said fuse tube, a guide tube carried by saidfitting through which said member is movable, an unlatching tubeslidebly telescoped over said guide tube for unlatching said fuse tube,a coil compression spring around said guide tube and inside saidunlatching tube biasing the same apart and arranged to be compressedwhen said member engages said unlatching tube, and a stop sleevetelescoped over said guide tube and acting to limit their relativemovement apart when said member engages said unlatching tube and movesthe same to prevent said spring from going solid.

3. In a dropout fuse construction, in combination, a fuse tube, aferrule at the lower end of said fuse tube having an annular grooveintermediate its ends, a detachable hinge fitting for receiving aportion of said ferrule, and a U-bolt in said groove extending throughsaid detachable hinge fitting and clamping the same to said ferrule,said lJ-bolt cooperating with the wall of said groove to resist endwisemechanical shock applied to said fuse tube and incident to interruptiontherein of heavy fault current.

4. In a dropout fuse construction, in combination, a fuse tube, aferrule at the lower end of said fuse tube having an annular grooveintermediate its ends, a detachable hinge fitting for receiving aportion of said ferrule, a U-bolt in said groove extending through saiddetachable hinge fitting and clamping the same to said ferrule, a radialmetallic flange secured to the upper end of said fuse tube, a detachablelatch terminal fitting overlying said flange, and bolt means extendingparallel to the longitudinal axis of said fuse tube and clamping saiddetachable latch terminal fitting to said flange.

5. In a dropout fuse construction, in combination, a fuse tube, metallicterminal means anchored to the ends of said fuse tube, a flangeextending radially outwardly from one of said terminal means, adetachable latch terminal fitting overlying said flange, a detachablehinge fitting for the other terminal means, locating means cooperatingwith said hinge fitting and the terminal means associated therewith formounting said hinge fitting in predetermined alignment with said latchterminal fitting, and clamp means detachably interconnecting saidterminal means and the respective fitting.

6. In a dropout fuse construction, in combination, a fuse tube, metallicterminal means anchored to the ends of said fuse tube, a flangeextending radially outwardly from one of said terminal means, adetachable latch terminal fitting overlying said flange, a detachablehinge fitting for the other terminal means, locating means cooperatingwith said hinge fitting and the terminal means associated therewith formounting said hinge fitting in predetermined alignment with said latchterminal fitting, bolt means extending parallel to the longitudinal axisof said fuse tube detachably clamping said latch terminal to saidflange, and clamp means detachably interconnecting said hinge fittingand said other terminal means.

7. In a dropout fuse construction, in combination, a fuse tube, metallicterminal means anchored to the ends of said fuse tube, a flangeextending radially outwardly from one of said terminal means, adetachable hinge fitting for the other terminal means, locating meanscooperating with said hinge fitting and the terminal means associatedtherewith for mounting said hinge fitting in predetermined alignmentwith said latch terminal fitting, bolt means extending parallel to thelongitudinal axis of said fuse tube detachably clamping said latchterminal to said flange, and a U-bolt extending around said otherterminal means and through said hinge fitting to detachably interconnectthe same.

8. In a dropout fuse construction, in combination, a fuse tube, metallicterminal means anchored to the ends of said fuse tube, a flangeextending radially outwardly from one of said terminal means, adetachable latch tcnninal fitting having a recess in one side forreceiving said flange, a detachable hinge fitting for the other terminalmeans, locating means cooperating with said hinge fitting and theterminal means associated therewith for mounting said hinge fitting inpredetermined alignment with said latch terminal fitting, bolt meansextending parallel to the longitudinal axis of said fuse tube and intosaid flange for detachably clumping said latch terminal thereto, andclamp means detachably interconnecting said hinge fitting and said otherterminal means.

References Cited in the file of this patent UNITED STATES PATENTS1,857,322 Nordhem May 10, 1932 10 Eck et a1 Dec. 26, Walsh Oct. 10,Marco Jan. 30, Schultz et a1 Dec. 9, Strobel July 20, Schultz et al Nov.7, Mosley June 4, Rawlins et a1. Sept. 11, Lindell Dec. 11,

